High-temperature superconductors are used, by way of example, in superconducting short-circuit current limiters for electrical distribution and transmission networks. A current limiter such as this makes use of the fact that a superconductor retains its superconductivity at an appropriately low operating temperature only for as long as the current density of a current flowing through it remains below a specific limit value, which is referred to as the critical current density. If a short circuit occurs in the corresponding power supply network, the current in the current limiter rises to a fault current which is greater than the critical value. This results in the superconductor changing to the resistive state, that is to say the voltage which is applied to the appropriate section of the power supply network is, at least in the short term, dropped entirely (in the event of a short circuit) or partially across the superconductor.
German Laid-Open Specification DE-A 197 46 976 describes a high-temperature superconductor arrangement for use in a current limiter. The arrangement has a superconducting layer and a perforated steel plate, which is in the form of an electrical bypass and forms a conductor assembly with the superconducting layer. In addition, the superconductor arrangement can be made mechanically robust and can be electrically insulated by means of fibre-reinforced composite materials, and is immersed in a liquid cooling medium which, for the sake of simplicity, is preferably liquid nitrogen (LN2), which is thermally insulated from the environment by a vessel which is referred to as a cryostat.
DE-A 198 32 274 describes a resistive current limiter with a conductor track structure composed of high-Tc superconductor material on an electrically insulating mount body. Straight conductor track sections are connected by means of annular, curved sections. The latter should have a maximum radius ratio of ra/ri=7 where ri is the inner radius of the section, and ra is the outer radius of the section. This avoids the current distribution, and hence the thermal load when limiting occurs, becoming inhomogeneous at kink points on the conductor track where the inner radii are too small. The minimum inner radius reduces the inhomogeneous local load to a tolerable level. However, at the same time, this makes the space utilization worse, that is to say the percentage of the mount body surface which is covered by the conductor track structure since, if the conductor track width is constant, the straight sections must be separated from one another by a specific minimum lateral separation at the turning points between successive, approximately parallel, straight sections.